ARH1 (YDR376W, UniProt P48360) – review notes

• Adrenodoxin reductase homolog, FAD flavoprotein (cofactor by similarity), essential PMID:9818721.
• Recombinant Arh1p reduces bovine adrenodoxin, ferricyanide and cytochrome c using NADPH (and NADH) PMID:9727014; inner-membrane localization by fractionation PMID:9727014. UniProt: EC 1.18.1.6 (adrenodoxin-NADP+ reductase, RHEA:42312) – GO represents this with GO:0004324 ferredoxin-NADP+ reductase activity (the old NADPH-adrenodoxin reductase term GO:0015039 is obsolete).
• Fe-S / iron homeostasis: PMID:11035018; PMID:12970193.
• CoQ: PMID:20534343.
• GOA lacks iron-sulfur cluster assembly for ARH1 although YAH1 carries it; Arh1 performs the NADPH-dependent reduction step of the electron chain feeding Isu1 -> proposed NEW (GO:0016226).
• Iron homeostasis (IMP) is a downstream consequence of Fe-S deficiency (iron regulon derepression) -> non-core.
• PANTHER PTHR48467 is named after glutamate synthase (module notes this; no PANTHER term asserted in the module).
• Not in YeastCyc pathways.

Audit to COMPLETE (2026-11-11)

• Deep research: no provider deep-research file is available (no API keys in this session).
• Oxidoreductase IBA/IEA rows changed from MODIFY to TOO_GENERAL (entailed by the accepted GO:0004324),
  consistent with the human FDXR review.
• NEW iron-sulfur cluster assembly kept after a comparator check (QuickGO, 2026-11-11): S. pombe arh1
  (O59710) carries GO:0044571 [2Fe-2S] cluster assembly (IC, PomBase) and Yah1 carries GO:0016226; human
  FDXR (P22570) carries no Fe-S assembly term. Arh1 supplies the electrons the step depends on
  PMID:12970193.